Department of Computer Scien

ce and Information Engineering

National Cheng Kung University

HANEL

8051 DATA MEMORY SPACEInterfacing to Large External Memory

‰In some applications we need a large amount of memory to store data

¾The 8051 can support only 64K bytes of external data memory since DPTR is 16-bit

‰To solve this problem, we connect A0 –A15 of the 8051 directly to the external memory’s A0 – A15 pins, and use some of the P1 pins to access the 64K bytes blocks inside the single 256K

×^8

memory chip